Telephone system.



H. l. HERINK.

TELEPHONE SYSTEM.

APPLICATION min JUNE 2.1911.

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H. J. HERINK.v TELEPHONE svsEM. APPLICATION FILED JUN 2, 191?.

Patented Deo. 17,1918.

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H. i. HERINK.

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H. J. HERINK.

TELEPHONE SYSTEM.

APPucATloN FILED luNE 2.1911.

Patented Dee. 17, 1918.

6 SHEETS-SHEET lwe Mor- UNITED STATES PATENT OFFICE.

HENRY JAMES HEBINK, 0F LONDON, ENGLAND, ASSIGNOB. T0 THE BELLY AUTOMATIC TELEPHONE COMPANY, LIMITED, OF LONDON, ENGLAND.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Dec. 1'7, 1918.

Application led .Tune 2, 1917. Serial No. 172,489.

To all whom t may concern:

Be it known that I, HENRY JAMES HERINK, a subject of the King of Great Britain, and resident of Marconi House, Strand, London, England, have invented a new and useful Improvement in Telephone Systems, of which the following is a specification.

This invention relates to telephone systems and particularly to means for preventing the registering of calls against a caller in certain conditions, as for examp (a) When a connection has been broken down owing to a circuit being or becoming defective.

(b) When on one of the parties being offered and accepting a trunk or other favored call, the operator severs the local connection before the termination of the conversation.

(c) When the called subscriber is busy.

My invention consists essentially in the provision of current varying means which in normal operating allow of the registration of a call against the party responsible for the connection and the breaking down of the connection partially or wholly, but in other conditions prevent the registration of a call against the party who originated the call and break down the connection partially or wholly.

The current varying means may consist of a polarized relay at one point operated by reversal of current at a control point, or a marginal relay inoperative to one strength of current and operative to another strength of current or any similar means.

It is now. usual to register calls at the conclusion of the conversation by the circuit changes brought about when the Vreceivers are replaced, and my invention allows the connection to be broken down in certain conditions without the register operating.

In manual systems or in semi-automatic systems in which the connecting and metering are controlled manually, I provide current varying means which cause signals and tones to advise the operator that the connection has been interrupted. The circuits are so arranged that the depression of a meter key is rendered ineffective to meter a call which has thus been interrupted, and the operator then removes the plugs, or otherwise restores the apparatus to normal. In one system described, when the signals are received, the junction is also automatically released and tests idle, although the plulg may not have been removed from the Jac In automatic systems the invention conslsts mainly in the provision of a polarized or marginal relay so placed that when energized it opens directly or indirectly the calling subscribers meter circuit, so that the meter does not register when a connection is broken down for the reasons specified before. This special relay is operated by a relay at a control point in a manner afterward to be described.

In the case of a connection on an automatic system, the guarding or release circuit is opened at the junction or trunk, or toward the subscribers line and-cut-ol relays, or at both points, by a polarized or marginal relay operated from the control point, so that the connection is broken down in such a way that the caller` receives a tone signal, and when he replaces his receiver his meter does not register.

In an automatic system, which may be of the electro-mechanical stepping type, or entirely of relays, manual equipment is usually provided for long distance or trunk calls, and as on manual systems such calls are privileged. An operator therefore offers the privileged call and if the party wanted for such call is engaged locally, ,but nevertheless accepts the privilegedv call, the local connection is broken down, but as the local conversation has not been completed no charge is to be made.

Generally speaking the invention consists in the use of a relay responsive to a particular kind or strength of current and arranged to be operated from a distant point over the talking circuit to prevent metering With or without. releasing the talking circuit or part of it. It may be used in any of the cases above stated and in connection with any talking circuit, but it is particularly suitable for multi-oiiice systems in which the exchanges are connected bv twowire junctions. For instance. in a talking connection extending over two or more manual or automatic or manual and automatic exchanges, relays of the kind mentioned may be connected to the line at several exchanges t o transmit an impulse from the distant exchange to a similar relay at the originating exchange, said relays operating to release the junctions between the exchanges and to prevent metering in the manner above described.

My invention is illustrated by the accompanying drawings in which- Figures I, Ia and Q show the necessary apparatus and circuits for manually connecting two subscribers stations. I

Figs. Ib and Ic show modifications.

Figs. 3, 4 and 5 show the necessary apparatus and circuits for automatically connecting two subscribers stations. I

Fig. 6 shows the circuits of an additional stage, and may be inserted between Figs. 3 and 4.

A connection between two subscribers each connected to diiierent manual exchanges will now be described.

In Fig. I, S represents the calling subscriber of the irst exchange A, L the line connecting S to A; T is the operators cord circuit, and T1 the outgoing trunk to the second exchange B.

Fig. Q represents the incoming end of T1 and B, and L2 the line connecting the required subscri'ber S1 to B.V

A calling subscriber lifting his recelver completes circuit I, energizing line relay LR which completes circuit Q, causing the calling lamp CL to glow in known manner. An operator, observing the call, inserts the answering plug AP into the calling Subscribers jack AJ, thereby completing circuit 3 and energizing the subscribers cut-oi? relay COR, but not subscribers meter SM; LR is thus cut out of circuit, causing CL to be extinguished.

Circuit 4 is also completed over the calling subscribers telephone and relay ASR is thereby energized, shunting lamp ASL by resistance R2 in circuit 3, ASL being thus dimmed. The operator throws the key K in the direction C connecting her telephone circuit to the calling line in known manner.

The subscriber gives in the number of the required exchange line, and the operator may ask for the connection over an order wire to the second exchange, or may place calling plug CP into the outgoing trunk jack CJ, thereby completing circuit 5 over the trunk 1, thus energizing relay CR in Fig. Q. Relays MCR and CSR are not energized owing to high resistance of CR. Relay COIR is also energized over circuit 6, calling super visory lamp CSL glowing. Relay COIR completes circuit 7, causing the engaging lamps EL1, EL2 and the like to glow, thus denoting engagement of the trunk. CR completes circuit 8, glowing supervisory lamp SQL, thus indicating a call to the operator at the second exchange. LSR energizes and partly connects up the circuit to the calling plug CIP. The second operator moves switch LK to connect up her telephone set at D to the trunk in known manner, and db'tains from the operator at the rst exchange the number required. She now inserts CIP into the required number CIJ, thus completing circuit 9, energizing S3R and CCQR, but not SIM. It will no/vsr be seen that circuit 8 is shunting circuit 9, the resistance of LSR being low-and causing SQL to be dimmed.

Ringing is now applied over CIP to the required subscribers line in known manner, and the subscriber `answering causes said ringing to be disconnected, and at the saine time completes circuit 10, energizing supervisory relay SIR which in turn completes circuit II, energizing relay MHR which, switching in circuit Ila, is rendered independent of circuit Il. SIR also switches in 5, shunting the high resistance Winding of CR with its low resistance winding. Consequently CSR is energized, but not MCR (Fig. I), which is biased against the normal working current, and lamp CSL is dimmed by being shunted by R in circuit 61. I is an impedance to balance CSR and MCR. The calling subscriber is now able to talk to the called subscriber, the successful establishment of the connection being indicated to the A exchange operator by the dimming of lamp CSL, and to the B operator by the continued dimming of SQL. If S replaces his receiver, circuit 4 opening denergizes ASR and lamp ASL then glows fully. Then S1 replaces his receiver, circuit 10 opening causes SIR to denergize, and opening circuit 5a cuts out low ing of CR which causes CSR to release its armature. CSR opening circuit 6a causes CSL to glow fully. The A operator, noting the glowing of ASL and CSL, depresses metering key MK, thereby switching in circuit 3b, in which is connected the operators p0- sition meter OSM which has an increa voltage connected to it. This increased voltage causes SM to operate, thus metering the call .against the calling subscriber. The A operator now withdraws AP and CP from jacks AJ and CJ, restoring all apparatus at exchange A to normal and causing circuit 5 to be opened. CR denergizes, thus removing the shunt from circuit 9 and deenergizing MHR. SQL now glows fully, and the B operator therefore withdraws CIP from CIJ, thus restoring all apparatus at the B exchange to normal condition.

Should the connection, when S is speaking to S1, be interrupted at the originating end and plug AP be withdrawn from jack AJ, it is obvious that meter SM will not be operated. If, however, the interruption occur at the second exchange 'by the withdrawal of CIP, relays SIR and S3R denergize, and SQL will new glow over circuit 8. now energizes over circuit IQ, and SQL will continue to glow over circuit 8b until this relay denergizes. EMR switches in circuits 5b and 5, the latter continuing to enerresistance wind-l gize relay CSR, and the former imposing an increased voltage, that is, varying the current, over one line of the trunk T", energizing meter control relay MCR which switches in circuit 13 and energizes meterpreventing vrelay MPR. This causes an interrupted tone to be given from TTT over interrupter INT, by circuit 14 to S. Lamp CSL now glows fully over circuit 6 owing to circuit 6" being broken by MPR. S replacing his receiver opens circuit 4 causing ASR to deenergize. thus opening 3 and causing ASL to glow fully. The A exchange operator may depress MK, but circuit 3" will not be established owing to MPR. Neither OSM nor SM will therefore operate. She will now withdraw the plug AP, opening circuit 3, thereby releasing COR and permitting S to rc1-call if he so desire. Plug CP being withdrawn opens circuits 5" and 5c to deenergize MCR, CSR and CR. Circuit 6 is also opened and COlR denergizes, opening circuit 7; lamps EL", EL2, and so on, cease to glow, indicating the release of T1. MPR also denergizes, therefore all apparatus at the A exchange is restored to normal.

CR (Fig. 2) denergizing opens circuit 11a. MHR denergizes, thus opening circuit 12. MMR is now denergized, causing SQL to be extinguished, thus returning all apparatus at B to the normal condition.

It is obvious that a modification may be made by so arranging the contacts on MPR that the depression of MK will allow OSM but not SM, to operate, so that the call may actually be recorded on the operators position meter, as shown in Fig. 1".

Fig. 2L illustrates means for preventing, in a manual exchange, the registering of a call against a caller if the wanted line is busy. If the wanted subscriber S1 be busy, the operator at exchange B will insert plug CIP into jack BJ, thereby completing circuit 13 through resistance R13. This results in the operation of SlR and consequent operation' of MHR. As there is no sleeve connection on jack BJ, SBR will not have become energized, so that MMR can operate as soon as MHR has become operated, and as stated above, can complete circuits 5" and 5 with the results already described.

Another modification which may be made is to arrange that the operation of MPR shall connect an interrupter similar to INT in circuit 6a, so that lamp CSL will flash,

indicating` to the A operator the breakdown of the connection. The operator, on throwing K. will receive tone from TTT. This is illustrated in Fig. 1. Normally CSL glows over circuit 60 and is shunted by 60" when CSR operates to dim it. If MPR is operated. CSL will be flashed by the interrupter in circuit 70, 60a being open at MPR and the sleeve circuit maintained over circuit 80.

Fig. 1a is a modification of Fig. 1. Its

operation is similar to Fig. 1, except that after MCR operates over circuit 5", MPR energizes over 13, opening. circuit 6*, but closing 6", so that CSL now glows fully. MPR disconnects circuits 5" and 5", therefore MCR and CSR denergize, but MPR maintains itself over 13". Busy tone is given to S over circuit 14, the connection E being attached to a coil TTT and an interruptcr INT similar to Fig. 1.

MPR is of high resistance, so that although it remains energized over 13, COlR (Fig. 1) denergizes, thereby opening circuit 7 and extinguishing engaging lamps EL. T1 istherefore free to be engaged by any other operator, the resistance of MPR preventing a busy test from being taken on the bush of jack CJ. On receiving the clearing signal from S, the operator at A will clear down the circuit in the manner described for Fig. 1.

A connection made between two subscribers stations in an automatic system, each directly associated with different exchanges, will now lbe described. A

In Figs. 3, 4 and 5, S2 is the calling subscribers station, L the line connecting the station to the first exchange A, T3 a trunk between A and the second exchange B, and L2 the llne between the latter exchange and the called subscribers station S3.'

S2 calls by lifting the receiver. Circuit 1 energizes line relay L2R and line L becomes connected over a pre-selector ,switch or relays to a junction T2, which has access to a first group switching stage. This is accomplished preferably by means of relays CR1 and CB2 in the manner described in application Serial No. 832,471, tiled 17th April, 1914. Circuit 2 is now completed and current feeding relay IR energizes. Circuit 3 energizes relay BSR over selector connecting relay SCR, and T2 becomes connected to an impulse responder or selector over the circuit marked AA. GR now energizes over circuit 4 and renders itself independent of BSR by switching in circuit 6. The latter relay is now maintained over circuit 5.

CO3R and AMR, but not subscribers meter S2M, energize over circuit 7, and FR energizing over circuit 7' LQR is denergized. S2 now sends in impulses in known manner and causes IR to denergize and reenergize successively. On the first impulse, IR denergizing, ICR energizes over circuit 8 and being slow to release remains energized during a complete train of impulses,

which are transmitted to the selecting device over circuit 9.

For the sake of clearness I will assume that the first train of impulses determines the selection of the second exchange B. At the completion of the train, ICR denergizes, SCR energizes over circuit 10 completed by the selector in any suitable manner (which is not here described as it forms no part of this invention), and T2 is connected -over C3R and @4R to T3 as described in Patent No. 1,195,771. The selecting device is then released,` circuits 5 and 9 are opened and relays BSR and SCR with CBR and C4R are maintained over circuit l1. During the sending` of impulses GR does not deenergizes as it is slow to release, owing to one of its windings being short-circuited over circuit 4B. T2 being connected to Ts establishes circuit 12. 12R energizes, but not S-lR nor polarized or marginal relay PR. BSlR energizes from the selecting device over circuit 13 and G1R, a slow release relay, energizes over 14 and, switching in 15,

vrenders itself independent'of BSlR, which is maintained over circuit 16. G1R opens circuit 12, but the loop circuit of T3 through 12R is maintained by circuit 12a completed owing to the operation of BSlR and G1R.

The second train of impulses is now sent in by S2. ICR renergizes and the impulses are therefore repeated over T3, thus causing ISR to denergize and renergize successively. 0n the first denergization of 12R, lClR energizes over circuit 17, and being slow to release does not denergize until the train of impulses is complete. The impulses are consequently repeated to a selector in the second exchange over circuit 18. When the second train of impulses is complete, ICR and IClR denergize, and SClR energized from the selectin device is with y BSlR maintained over clrcuit 19 in series with CR and CGR. T3 is extended to Ti by another selecting device (over whose contacts 19 is completed) to which subsequent impulses` are sent in the manner described. Eventually, when all the selecting is complete, relay FTR becomes energized over 1.8a formed by the final selecting device in any suitable manner, not being part ofthis invention but substantially similar to the manner of operating .the connecting relays described in Patent No. 1,195,771 and application Serial No. 832,471, and circuit 19 is extended to this relay over contacts of RR which is operated by T4 becoming connected, in a manner substantially similar to that described in application Serial No. 832,471, to L2 by relays C7R and CSR and with COLR energized over circuit 20. The called subscribers meter SSM does not energize. FlR has also energized over circuit 20B. The selector releasing itself, relays BS1R, SCIR, C5R, CR and FTR are maintained in series over circuit 19.

Ringing current is now applied to S3 over circuit 21, but RGR does not energize until S3 removes his receiver. when its second winding is switched in in place of RR. rlhe latter relay denergizes, cutting out the lirst winding of RGR which continues to be energized with C7R, CSR and CO4R over 22.

Ringing current is also removed from L and relay S5R therefore energizes over circuit 23. yCLR now energizes over 24:V and RCR energizes over 25, cutting out relay 12R. G1R does not denergize, being maintained over circuit 26. The lowest contact is the last to open on relay RCR, so that relay CLR does not denergize, but is maintained over circuit 27. The resistance of the winding of CLR is such as to energize SiR, but not PR (Fig. 3) which is biased against the normal working current. MR new energizes over 28, and will maintain itself over circuit 29 even if SLR be denergized. Relay GR is now no longer slow, its second winding being no longer short-circuited owing to circuit 4.a being opened. S2 is new free to speak to S3 over circuits 30 and 23 and repeating coil R. If Ss replaces his receiver, S5R denergizes, but does not release the circuit. S2 controls the release, and on replacing his receiver opens circuit 2 and causes IR to denergize. This closes circuit 4J and switches in the second winding of GR as a shunt to circuit 7, AMR continuing to remain energized. The first winding of GR is now receiving current over circuit 31, and though the windings are dierentially wound GR does not yet fall 0E, there being a balance in favor of circuit 31.

The increased current in circuit 7 due to the shunt causes S2M to energize, and metering the call, short-circuits CO3R over 7. The current in the second winding of GR is now increased, and is sufiicient to cause it to denergize, thus releasing all the relays (shown in Fig. 3) hitherto remaining energized, and disconnecting L from T2 and T2 and T3. CLR consequently denergizes, thereby releasing all relays shown in Figs. f1 and 5, also releasing 'l5 from T4 and '14t from L2.

Suppose that when S2 called S5, the latter subscriber was engaged on another call, the final selecting device would be unable to complete the operating circuit of CSR, as the circuit would be broken owing to Ss being engaged. The method of breaking this circuit forms no part of this invention, but it may be stated generally that the circuit is taken through normally resting contacts of relay COLLR which, as stated, becomes operated if S3 be engaged. As CSR cannot operate, RR and RCR are disabled so that circuit 19 would not be completed, resulting in the release of BSIR, SClR, CR, CGR and FTR. Circuit 32 is completed by the denergization oit BSlR operating PR, which will cause the release of all trunks and apparatus pertaining thereto in the manner explained, without causing S2M to operate. Tone will be given to S2 over circuit 7 d, until he clears by replacing the receiver on the hook switch.

l will now assume that S2 has been connected to S' in the manner described and that the former is required `for a special call. A line manually or automatically operated obtains access to line L by known-means and S2 is requested to take the call. If he accedes`to the est, a potential is applied to the maintaining wire of the connection in known manner, as, for instance, by temporarily depressin key RRK, thus shortcircuiting CB1 am? CR2, also AMR by circuit 7", them to denergize and disconnect circnit 2. IR and then GR- denergize, rel all apparatus beyond the subscribers line and rendering the trunks accessible to other calls. The calling subscribers meter being disconnected from T2 does not receive the current necessary to operate it, and consequently no metering takes place. The special call would take place over 30, CO3R remaining energized over 7" and LR being cut out.

The denergization of G1R in Fig. 4 opens circuit 19, and FTR denergizing opens circuit 22. C'R and CSR denergize, releasing Tf from L2. CO4R denergizes but FIR maintains itself over circuit 23B. S3 receives a tone from tone coil TQT denoting that the line to which he was connected is now occupied with another call. Sa on replacing his receiver opens circuit 23 and FlR deenergizes, thus all apparatus is now normal. S2 is now busy, and CO3R being energized, a false call cannot be made. The opning of circuit 7b releasing COBR causes F to remain energized over 7d, unless S2 has already replaced his receiver, when FR also denergizes. When S2 re-calls by relifting his receiver, a fresh call is initiated in the manner already described.

Let us now suppose that while S2 and S3 were talking, S3 was required for a special call. Connection would be made to his line in known manner from jack CRlJ (Fig. 5), and on Ss accepting such call, an increased voltage is applied by any known method, v

for instance, the temporary depression of RIRK. This causes C7R, CSR and RGR to denergize over 20", but CO4R continues to be maintained over` 20", a voltage being applied by the means at CRIJ. The special call may now talk to S2 over 23", L2 being disconnected from T4. L3R is not at any time switched in circuit. RGR opens circuit 19; consequently C5R, CGR, SClR and BSlR all denergize, freeing T3 from T. BSlR causes S5R to denergize, but RCR maintains itself over circuit 25a. BSlR also opens circuit 30 and varies the current, that is, applies a high voltage to one line branch of Ts over circuit 32 through resistance R. PR (Fig. 3) immediately energizes, opening circuit 7. CLR denergizes and opens circuit 26, causing G1R to dec-nergize, which in turn opens circuit 25a and causes RCR to denergize. These two relays are slow to release, so that 12R on this connect-ion cannot renergize owing to BSR releasing C3R and C4R, and disconnecting T2 from T2, the latter trunk now being available for a fresh call.

At the irst exchange (Fig. 3) PR opens circuit '7 CR. CR2 and AMR denergizc. S2 receives tone over circuit 7 d in the manner described, indicating the occupation of S2. (R denergi'zes (due to the breaking of circuit 4 by IR and circuit 31 by AMR) causing the break of circuit 11 and consequent release of BSR. Trunk T2 is thus rendered available for a fresh call.

S2 on replacing his telephone opens circuit 7d and FR denergizes, so that S2 may make a new call if he so desires.

A connection set up by a calling subscriber S2 connected to the first exchange A, to S3 a subscriber connected to a third exchange B, said connection to be established through an intermediate exchange D, will now be described. Y In this connection it will be necessary to examine further Figs. 3, 4, 5 and 6.

Fig. 3 represents the first exchange with outgoing trunk T3 leading to the second exchange D shown in Fig. 6 with trunk TT leading to the third exchange shown in Fig. 4, which connects to S3 in Fig. 5 as before described.

The setting up of the connection between the two exchanges is made in a manner obviously similar to that already described. For example, the first digit impulses may choose T2, the second set TT (Fig. 6) and the third and fourth sets may choose called subscriber S2' as before described.

In the operations, when T3 is connected to exchange D (Fig. 6), 13R operates, operating BS2R over circuit 34. G2R now operates over 34, closing 34", While BS2R is now maintained over 35. S2 sends in the second train of impulses. IR responds as before, repeating said impulses over T3 (Fig. 3) and T2 (Fig. 6) to 13R, which also ,responding repeats them to a selecting device in D. At the cessation of this train 'of impulses, T3 is connected at TT, BS2R being now maintained over circuit 36. The third and fourth trains of impulses are now sent in, IR repeating to 13R which repeats over TT to I2R which repeats into a selecting device. Eventually said selecting device is released, and S2 becomes connected to Ss in the manner previously described.

During the repeating of impulses, IC2R Fig. 6) operates over circuit 37 in a manner similar to ICR, thus removing condensers K and K1, and relays PlR and SGR from the trunk. S2 is now free 4to converse with S2, SSR but not PIR becoming operated over TT by relay CLR (Fig. 4) circuit 38, which operates CLlR over 39; RClR operates over circuit 40, maintaining over 40a, while c; p tasa-air GQR maintains over 41. S4R operates over 42, thus operating MR as before described.

It is obvious that if S2 replaces his receiver, IR denergizing causes metering Ito take place on SM, and denergizing GR releases the circuit owing to all CR relays deenergizing. Consequently CLIR (Fig..6) denergizes, causing G2R to denerglze. Thus this portion of the circuit is released. CQR and CIOR denergizing release the circuit shown in Figs. 4 and 5 in a manner similar to that already described.

If S3 had been engaged on another call, the release of the nal selecting device releases BSIR, SCIR, C5R, C6R and FTR, thereby causlng PIR and in turn PR to energize. This releases the trunks without causing metering, in the manner explained, tone being given to S over circuit 7 d until he replaces his receiver.

It is also obvious that if the connection had been interrupted at the originating end, all circuits and trunks would have been released without causing metering.

If the interruption had taken place at the called end causing C7R and CSR to deenergize, BSIR denergizing sends a reversed current over circuit 43, thus energizing PIR. This opening circuit 36 denergizes BSQR, SCZR, C9R, CICR, and thereby releases all apparatus and trunks leading to exchange B. BSQR completes circuit 44 and energizes PR (Fig. 3), thus causing the release of all apparatus and trunks Without causing metering, in the manner already described.

It may also be seen that even if a connection be interrupted at any stage, it will cause instantaneous release without metering against the calling party.

What I claim is:

l. In a telephone system, the combination of a calling subscribers line, a meter connected therewith, a called subscribers line and means associated with a circuit connecting these lines for producing, on disconnection of that circuit, a variation in current strength to prevent the meter being operated.

2. In a telephone system, the combination of a calling subscribers line, a meter connected therewith, a called subscribers line and means associated with a circuit connecting these lines for producing, on disconnection of that circuit ra reversalof current to prevent the meter being operated.

3. In a telephone system, the combination of a calling subscribers line, a meter connected therewith, a called subscribers line and current varying means associated with a circuit connecting these lines and adapted, on disconnection of that circuit, to prevent the meter being operated and to release the connection.

4. In a telephone system., the combination of a calling subscribers line, a meter connected therewith, a called subscribers line and means associated with a circuit connectmg these lines for producing, on disconnectlonof that circuit, a variation in current strength to prevent the meter being` operated and to release the connection.

5. In a telephone system, the combination of a calling subscribers line, a meter connected therewith, a called subscribersline and means associated with la circuit connecting these lines for producing, on disconnection of that circuit, a reversal of current to prevent the meter being operated and to release the connection.

6. In a telephone system, the combination of a calling subscribers line, a meter connected therewith, a trunk line, a called subscribers line, current varying means associated with the circuit comprising the two subscribers lines and the trunk line and adapted, on disconnection of the circuit, to prevent the meter operating and to release the connection and means for giving tone signals to the calling subscriber and to the trunk-line.

7. In a telephone system, the combination of a calling subscribers line, a meter connected therewith, a trunk, a called subscribers line, devices for feeding current to the trunk and a relay associated with such devices biased against the normal Working current and adapted to respond to a current change to prevent the meter being operated.

8. In a telephone system, the combination of a calling subscribers line, a meter connected therewith, a trunk, a called subscribers line, devices for feeding current to the trunk, a relay associated with such devices biased against the normal working current and adapted to respond to a current change to prevent the meter being operated and means for giving tone signals to the calling subscribers line.

9. In a telephone system, the combination of a calling subscribers line,a meter connected therewith, a trunk, a called subscribers line, devices for feeding current to the trunk and a relay associated with such devices biased against the normal working current and adapted to respond to a current change to prevent the meter being operated and simultaneously to disconnect the calling y subscribers line from the trunk.

I0. In a telephone system, the combination of a calling subscribers line, a meter connected therewith, a called subscribers line, means normally dependent upon the operation of the meter for releasing the connection between the lines and means adapted to be -temporarily associated with the calling line for holding it energized and for 'breaking down the remainder of the connection without the meter being operated.

Il. In a telephone system, the combination of a calling subscribers line, a cut-olii' relay and meter connected therewith, a called subscribers line, means for connecting the two lines, means normally dependent upon the operation of the meter Jfor releasing the connection and means adapted to connect -suitable potential between the cut-off relay and the meter so that the cut-oli relay is held energized while the meter is caused -to deenergize.

12. In a telephone system, the combination of a calling subscribers line, ameter connected therewith, a called subscribers line, means for connecting the two lines, means normally dependent upon the operation of the meter for releasing the connection and means adapted to be associated with the called line for holding it energized, for breaking down the' connection and for preventing the operation of the meter.

13. In a telephone system, the combination of a calling subscribers line comprising a third conductor, a meter connected therewith, a cut-oli relay, a called subscribers line, means for connecting the two lines, means normally dependent upon the operation of i the meter for releasing the connection, a biased relay adapted to open the meter cir cuit, means adapted to be temporarily associated with the called subscribers line for holdin it energized and means for connecting. sultable potential between the cut-oil' relay and the meter for holding the cut-0E relay energized and for actuating the biased relay.

14. In a telephone system, the combination of a calling subscribers line, a meter connected therewith a device for feeding current to the tru a called subscribers line, a biased relay associated with the lcurrent feeding device and adapted to prevent the meter being operated, means for varying the current in the circuit comprising the two lines and the trunk and means adapted to be temporarily associated with the called line for actuating the current varying means.

15. In an automatic telephone system, the combination of a calling subscribers line, a meter connected therewith, a called subscribers line, means for connecting the two lines, means normally dependent upon the operation of the meter for releasing the connection and means for releasing the connection without the operation of the meter.

16. In a telephone system, the combination of an exchange, a calling subscribers line connected thereto, a meter connected to such line,l a second exchange, a called subscribers line connected thereto, a trunk conv necting the two exchanges, means adapted to be temporarily associated with the calling line for holding such line energized, for breaking down the remainder of the connection and for preventing the meter being operated.

17. In a tele hone system, the combination of an exc ange, a calling subscribers line connected thereto, a meter connected to such line, a second exchange, a called subscribers line connected thereto, a trunk connectingl the two exchanges, means adapted to be temporarily associated with the called line for holding such line energized, for breaking down the connection and for preventing the meter being operated.

In testimony that I claim the foregoing as my invention I have signed my name this eighth day of May, 191

HENRY JAMES HERINK. 

